THE ability of tropical forests to recover from gold mining activities has remained largely unquantified, an international study led by the University of Leeds has revealed.

The study is said to be the first to provide detailed field-based information on the regeneration of forests in Guyana after gold mining, and the first ground-based estimate of carbon sink lost as a result of gold mining activities across the Amazon.

The study estimated that mining-related deforestation results in the annual loss of over two million tons of forest carbon across the Amazon. The lack of forest regrowth observed following mining suggests that this lost carbon cannot be recovered through natural regeneration.

The team’s findings, published in the Journal of Applied Ecology, found that forest recovery rates on abandoned mining pits and tailing ponds are amongst the lowest ever recorded for tropical forests. At some sites there was nearly no tree regeneration even after three to four years since mining had stopped.

Lead author, Guyanese Dr Michelle Kalamandeen, now a post-doctoral researcher at the University of Cambridge (UK) and Laurentian University (Canada) said: “This study shows that tropical forests are strongly impacted by mining activities, and have very little capacity to re-establish themselves following mining. Our results clearly show the extraction process has stripped nitrogen from the soil, a critical component to forest recovery, and in many cases directly contributed to the presence of mercury within neighbouring forests and rivers. Active mining sites had on average 250 times more mercury concentrations than abandoned sites.

“Not only does this have serious consequences for our battle against global warming by limiting Amazonian forests’ ability to capture and store carbon, but there is also a larger implication of contaminating food sources, especially for indigenous and local communities who rely on rivers. A positive finding from this study shows that overburden sites, areas where topsoil is deposited during the mining process, recorded similar recovery rates as other Central and South American secondary tropical forests abandoned after agriculture or pasture.

“We could be facing a race against the clock. The current crisis is significantly increasing the demand for gold, given its perceived role as an economic stabiliser. With current gold price more than US$1700 per ounce and estimated to reach US$2000-3000 in the coming months, many artisanal and small-scale miners are already rapidly responding to this increase in pricing, and the weakening of environmental laws and policies as we’ve seen in Brazil, leading to further deforestation in the Amazon…”